[MemoryLocation] Support memset_pattern{4,8} in getForArgument.

[fhahn]

Summary

memset_pattern{4,8} behave as memset_pattern16, with the only difference
being the size of the pattern location.

llvm/lib/Analysis/MemoryLocation.cpp

case LibFunc_strncpy: {
         // strncpy is guaranteed to write Len bytes, but only reads up to Len
         // bytes.
         Size = ArgIdx == 0 ? LocationSize::precise(Len->getZExtValue())
                            : LocationSize::upperBound(Len->getZExtValue());
       }
       return MemoryLocation(Arg, Size, AATags);
     }
     case LibFunc_memset_pattern16:
+    case LibFunc_memset_pattern4:
+    case LibFunc_memset_pattern8:
       assert((ArgIdx == 0 || ArgIdx == 1) &&
              "Invalid argument index for memset_pattern16");
-      if (ArgIdx == 1)
-        return MemoryLocation(Arg, LocationSize::precise(16), AATags);
+      if (ArgIdx == 1) {
+        unsigned Size = 16;
+        if (F == LibFunc_memset_pattern4)
+          Size = 4;
+        else if (F == LibFunc_memset_pattern8)
+          Size = 8;
+        return MemoryLocation(Arg, LocationSize::precise(Size), AATags);
+      }
       if (const ConstantInt *LenCI =
               dyn_cast<ConstantInt>(Call->getArgOperand(2)))
         return MemoryLocation(Arg, LocationSize::precise(LenCI->getZExtValue()),
                               AATags);
       return MemoryLocation::getAfter(Arg, AATags);
     case LibFunc_bcmp:
     case LibFunc_memcmp:
       assert((ArgIdx == 0 || ArgIdx == 1) &&
case LibFunc_memccpy:
               dyn_cast<ConstantInt>(Call->getArgOperand(3)))
         return MemoryLocation(
             Arg, LocationSize::upperBound(LenCI->getZExtValue()), AATags);
       return MemoryLocation::getAfter(Arg, AATags);
     default:
       break;
     };
   }
-  // FIXME: Handle memset_pattern4 and memset_pattern8 also.
 
   return MemoryLocation::getBeforeOrAfter(Call->getArgOperand(ArgIdx), AATags);
 }

llvm/test/Analysis/BasicAA/libfuncs-darwin.ll

 ; RUN: opt -mtriple=x86_64-apple-macosx10.7 -inferattrs -basic-aa -aa-eval -print-all-alias-modref-info -disable-output 2>&1 %s | FileCheck %s
 
 declare void @memset_pattern4(i8*, i8*, i64)
 declare void @memset_pattern8(i8*, i8*, i64)
 declare void @memset_pattern16(i8*, i8*, i64)
 
 define void @test_memset_pattern4_const_size(i8* noalias %a, i8* noalias %pattern) {
 ; CHECK-LABEL: Function: test_memset_pattern4_const_size
 ; CHECK:       Just Mod:  Ptr: i8* %a <->  call void @memset_pattern4(i8* %a, i8* %pattern, i64 17)
 ; CHECK-NEXT:  Just Ref:  Ptr: i8* %pattern <->  call void @memset_pattern4(i8* %a, i8* %pattern, i64 17)
 ; CHECK-NEXT:  Just Mod:  Ptr: i8* %a.gep.1 <->  call void @memset_pattern4(i8* %a, i8* %pattern, i64 17)
-; CHECK-NEXT:  Just Mod:  Ptr: i8* %a.gep.17  <->  call void @memset_pattern4(i8* %a, i8* %pattern, i64 17)
+; CHECK-NEXT:  NoModRef:  Ptr: i8* %a.gep.17  <->  call void @memset_pattern4(i8* %a, i8* %pattern, i64 17)
 ; CHECK-NEXT:  Just Ref:  Ptr: i8* %pattern.gep.3 <->  call void @memset_pattern4(i8* %a, i8* %pattern, i64 17)
-; CHECK-NEXT:  Just Ref:  Ptr: i8* %pattern.gep.4 <->  call void @memset_pattern4(i8* %a, i8* %pattern, i64 17)
+; CHECK-NEXT:  NoModRef:  Ptr: i8* %pattern.gep.4 <->  call void @memset_pattern4(i8* %a, i8* %pattern, i64 17)
 ;
 entry:
   call void @memset_pattern4(i8* %a, i8* %pattern, i64 17)
   %a.gep.1 = getelementptr i8, i8* %a, i32 1
   store i8 0, i8* %a.gep.1
   %a.gep.17 = getelementptr i8, i8* %a, i32 17
   store i8 1, i8* %a.gep.17
 
entry:
   ret void
 }
 
 define void @test_memset_pattern8_const_size(i8* noalias %a, i8* noalias %pattern) {
 ; CHECK-LABEL: Function: test_memset_pattern8_const_size
 ; CHECK:       Just Mod:  Ptr: i8* %a <->  call void @memset_pattern8(i8* %a, i8* %pattern, i64 17)
 ; CHECK-NEXT:  Just Ref:  Ptr: i8* %pattern <->  call void @memset_pattern8(i8* %a, i8* %pattern, i64 17)
 ; CHECK-NEXT:  Just Mod:  Ptr: i8* %a.gep.1 <->  call void @memset_pattern8(i8* %a, i8* %pattern, i64 17)
-; CHECK-NEXT:  Just Mod:  Ptr: i8* %a.gep.17  <->  call void @memset_pattern8(i8* %a, i8* %pattern, i64 17)
+; CHECK-NEXT:  NoModRef:  Ptr: i8* %a.gep.17  <->  call void @memset_pattern8(i8* %a, i8* %pattern, i64 17)
 ; CHECK-NEXT:  Just Ref:  Ptr: i8* %pattern.gep.7 <->  call void @memset_pattern8(i8* %a, i8* %pattern, i64 17)
-; CHECK-NEXT:  Just Ref:  Ptr: i8* %pattern.gep.8 <->  call void @memset_pattern8(i8* %a, i8* %pattern, i64 17)
+; CHECK-NEXT:  NoModRef:  Ptr: i8* %pattern.gep.8 <->  call void @memset_pattern8(i8* %a, i8* %pattern, i64 17)
 ;
 entry:
   call void @memset_pattern8(i8* %a, i8* %pattern, i64 17)
   %a.gep.1 = getelementptr i8, i8* %a, i32 1
   store i8 0, i8* %a.gep.1
   %a.gep.17 = getelementptr i8, i8* %a, i32 17
   store i8 1, i8* %a.gep.17